In the past, there has been known in medical fields and industrial fields an endoscopic device using an image sensor to image the interior of an observation object such as a human being or a machine structure, and thereby to observe the interior of the observation object (see Patent Literature 1, for example).
The endoscopic device according to Patent Literature 1 is an endoscopic device with a detachable head including: an imaging device (hereinafter described also as a camera head) which includes an image sensor; a controller to control the image sensor; and a cable electrically connecting between the imaging device and the controller and configured to transmit various signals therebetween.
Accordingly, the endoscopic device according to Patent Literature 1 employs high-capacity optical transmission in consideration of the fact that image data output by the image sensor contains a large amount of information.
Specifically, the camera head includes the image sensor and a printed board electrically connected to the image sensor. On the printed board, there is mounted a photoelectric conversion element converting, into optical signals, imaging signals (electrical signals) output by the image sensor and relayed by the printed board.
Meanwhile, the cable is formed of a composite cable including electrical wires for transmitting electrical signals and an optical wire for transmitting optical signals. The electrical wires are electrically connected to the printed board, and transmit, to the printed board (image sensor), control signals and the like (electrical signals) output by the controller. The optical wire is connected to the photoelectric conversion element, and transmits, to the controller, optical signals (imaging signals) obtained through conversion by the photoelectric conversion element.